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Page 1

COOLING TOWERS

SECTION 1

OPERATION AND CONSTRUCTION

'There aTe exhibits placed in the center of Ihe book that will be referred
to later in the program. The1J should be removed and set aside now so
Ihal they will be handy when needed.

1. A refinery uses as much as 25 barrels of water for every barrel
of crude processed.

A 200,OOO·bal'l'ei-a-day refinery might use as much as
_______ barrels of water.

. 2. Of all the water used by a refinery, 80 to 90 % is used as cool-



ant to absorb energy.

3. Look at tn15 heat exchanger.

HOT

COOL
~-LIQUID

As the liquid travels through the pipe, the heat from the
liquid is exchanged or transferred to the ______ _

4. Heat always travels from areas of higher te'mperature to ·areas
of (higher / lower) temperature.

5(, Water can absorb only so much heat.

As water becomes hotter, its effectiveness as a coolant (in-
creases / d ocreases).

6. After a while, the temperature of t~e water becomes so hillh
that it can no longer absorb from the hot
liquid .

7. The water in this heat exchanger works as a coolant only as
long as it is than the liquid being cooled.

8. Maximum cooling IS achieved by constantly replacing hot
water with _______ water.

1



5,000,000

heat

water

lower

decreases

heat

cooler

coo1

Page 2

9. In order to provide for further cooling, two things are possible.

First, the hot cooling water can be discharged and ____ _
with fresh water.

10. Or, the hot cooling water can he _______ and reused
(or further cooling.

11. The amount oC water needed for cooling in a large refinery is
in the range of (tho.usands/millions) of barrels per day.

12. Drawing millions of barrels o( water per day from the water
supply would be extremely ______ _

13. The amount of water needed is so large that many water sup-
plies (would /would not) be able to provide enough.

14. A refinery must be careful about the quality of the water it
discharges.

Discharging millions of barrels of hot water per day might
cause a problem.

15. Cooling the hot water enables the refinery to _____ _
water over and over again.

16. The liest way to handle hot water is to (discharge it / cool and
reuse it).

17. Hot water is cooled for reuse in special cooling __ .. __ _

MmlODS OF HEAT TRANSFER

18. Suppose a steel rod is heated at one end.

c

(The entire rod heats up evenly./Section A gets hot first.)

19. AJ3 s~tion A becomes hot, it acquires thermal, or ____ _
energy.



20. Thermal, or heat, energy always travels from higher to
_______ temperature regions.

2

replacE'(t

cooled

millions

co~tly, or expE'nsive

would not


pollution

reuse

cool and reuse it

tower!:::

",

Section A gets hot first.

heat

lower

Page 22

189. The operator must lubricate equipment regularly and
all equipment daily for other conditions

which require repair or replacement.

CONDITIONS AFFECTING COOLING TOWER PERFORMANCE

190. The most important factor in any kind of cooling tow. r is how
fast the water _____ _

191. Therefore, any condition which prevents water from evapo-
rating .'. the efficiency of the cooling tower.

192. Air contains moisture or water vapor.

On a damp day, the air holds (a lot of/ very little) water.

193. If the air surrounding a cooling tower is very humid, the water
in the cooling tower does not evaporate as much as it would
if the air was ______ _

194. On damp, humid days, a cooling tower works (bet.ter than/
not as well as) it does on dry days.

195. One factor that affects the rate of evaporation is the amount
of in the air in contact with the \vater.

Absolute and Relative Humidity

196. Air becomes denser as the temperature decrea.,"s.

Air is densest when temperatures are (very hot / very cold ).

197. More moisture can be contained in air if it is less dense.

Very cold air can contain (more/ less) moisture than hot air.

198. Temperature (is/ is not) an important factor in measuring
humidity.

199. Here is one way to express humidity measurements.

Suppose we have a humidity measurement that reads 1 pound
of water in 10 pounds of air. This reading is expressed as
(degree of saturation/ weight per given volume) .

200. Pound is an expression of a specific quantity.

1 pound and 10 pounds are (relative/ absolute) expressions
of quantity.

201. Humidity expressed as weight per quantity is (relative /
absolute) humidity.

202. Temperature is not considered in measurements of absolute
humidity.

~:t>solute humidity readings tell how much water is in a given
quantity of air, but (do/ do not) tell how much more water

. the air can absorb.

16

,
check. or jnspe\;~

evaporates

reduces

a lot of

dry
o.

not as well as

humidity. or moisture

very cold

less

is

weight per given volume

a0so1ute

absolute

do not

Page 23

. order tc... know how much evaporation can take place, it is
_sary to know how much more the air

absorb.

ipposewe have a humidity reading that says air at 85 0 holds
of the maximum it could hold at that temperature.

~~\~~~I;'~S expressed as (degree of saturation/ weight per

humidity reading is given ~ a "p~rcentage of maximwn

Humidity "erprE:S.Sed as a fJf:'T~ntage Cot maximum humidity at
a given tan~tU!e is (rtlative / e;bso\utE: / humidity.

206. A reIati..-~ humidity reading (doc do.,; not) give an indica·
tion of how much more wa"ter air can absorb.

207. If air bolds all the water vapor it can hold at any temperature,
it is aaid to be _____ _

.208. The relative humidity of air at the point of saturation lS

-----0/0.
209. AJ. relative humidity increases, evaporation _____ _

210. Th~\.performance of a cooling tower (increases/ decreases) as
the relative humidity increases.

211. Relative humidity is the (least/ most) important variable af·
fecting the performance of cooling towers.

Dry.and Wet-Bulb Temperatures

212. This combination of thermometers and wick is a hygrometer.

'"

THERMOMETER

The thermometers are identical except that one bulb is covered
bya _____ _

17

water .

degree of saturatio_n

relative

doos

saturated

100

decreases

decreases

most

' "



wick

Page 43

~,
152. Phenolphthalein in 4.0 pH water is _____ _

153. If applied excessively, the chlorine and phenolic compounds
used as rf i~infectants and algaecides are to
the wood in cooling towers.

154. Excess alkalinity over a long period of time is damaging to
cooling tower lumber. Water which is damaging to lumber is
likely to have a (high/low) pH value.

155. Wood contains organic acids which act to protect 'it from
rotting.

These acids can be washed out by _______ sub-
stances with high pH values.

156. Excessive chlorine also destroys the natural preservatives in
cooling towel' wood .

Excessive ______ _ and excessive
should be avoided,

REVIEW AND SUMMARY

157. Water for cooling is (readily available/ scarce) in most areas.

158. Water has the capacity to absorb (more/ less) heat than most
available coolants,


159. Water is (more/ less) costly than other possible coolants.

.160. Water from natural sources (is/is not) corrosive to metals.

d'.IIil. Water (has / does not have) scale-forming 'and fouling
tendencies.

162. Water is non-eombustible and therefore does not add to
dangers from fire.

It also responds readily to a large variety of ______ _
treatments.

153. Accumulation of suspended solids in cooling water may be
reduced by filtration, adding soft water,
sedimentation, and continuous from the
system.

164. In cloling W81.-.er, the main problem with hard water makeup
is that it (does not evaporate Quickly/increases scale.fonning
tendencies) ,

',.
i 165. Lime-soda and zeolite processes are used to ____ -,-__

water.

37

. ,
colorless'"

high

alkaline

,: .
. '.

ti i,..\ ~ . '.;.":

' ..
" \

. ! . · ; ,'
"

· •
alkaline; <:hlorine ~, '" .

'". ", , ~, , ,r·;.j . ..
' ,:.: "

-.., .
,! •.
,,1, ~

readily:,aVailabj~

more

less

IS

has

r ..

-.s;
)t.
" ..
~~

chemical, or
, ~
·fl. ... ,
f '

makeup "
blowdown'~' '

~ ,

increases

soften

, ... .

Page 44

166. The pH value is an expression of (hardn., --softness/acidity-
alkalinity) of the water.

167. Water with a pH value of 3.9 is ______ _

Water with a pH value of 7.9 is ____ ____ .

168. Water with a pH value of 7.0 is ______ .

169. Algae and slime are (mineral / biological) m:-\ter.

170. Algae occurs' mostly where water is expo od to (darkness/
sunlight).

171. Algae and slime cause heat exchanger __ ____ _

172. Coagulation is a process which may be aid .d by the use of

17&. -Coagulation aids (tiltration only /sedime,' cation only/both
tiltration and sedimentation) .

. 174. Gases, especially oxygen and hydrog.., sulfide, cause
______ of metal parts.

175. A process for protecting metal equipmen' against electro·

. ,'.'

.. . : .

chemical corrosion is prot· ction.

I THE END I



38

, -

acidity-alkalinity

acid

alkaline

nelltral

biological

sunlight

fouling, or cloggin;'

chemicals
- '.

both tiltration and
sedimentation

corrosion

cathodic

. ' ,' .. -,

_ ..

-,
--

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